首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12221篇
  免费   990篇
  国内免费   60篇
耳鼻咽喉   73篇
儿科学   287篇
妇产科学   198篇
基础医学   1550篇
口腔科学   222篇
临床医学   1608篇
内科学   2356篇
皮肤病学   165篇
神经病学   1255篇
特种医学   443篇
外国民族医学   1篇
外科学   2002篇
综合类   199篇
现状与发展   1篇
一般理论   9篇
预防医学   1006篇
眼科学   224篇
药学   919篇
中国医学   47篇
肿瘤学   706篇
  2023年   52篇
  2022年   36篇
  2021年   223篇
  2020年   131篇
  2019年   203篇
  2018年   274篇
  2017年   196篇
  2016年   201篇
  2015年   225篇
  2014年   379篇
  2013年   471篇
  2012年   743篇
  2011年   897篇
  2010年   420篇
  2009年   422篇
  2008年   664篇
  2007年   791篇
  2006年   647篇
  2005年   733篇
  2004年   618篇
  2003年   603篇
  2002年   595篇
  2001年   236篇
  2000年   263篇
  1999年   253篇
  1998年   164篇
  1997年   129篇
  1996年   129篇
  1995年   107篇
  1994年   98篇
  1993年   98篇
  1992年   156篇
  1991年   132篇
  1990年   138篇
  1989年   133篇
  1988年   130篇
  1987年   132篇
  1986年   111篇
  1985年   145篇
  1984年   118篇
  1983年   87篇
  1982年   76篇
  1981年   84篇
  1980年   69篇
  1979年   79篇
  1978年   67篇
  1977年   66篇
  1976年   59篇
  1974年   46篇
  1972年   46篇
排序方式: 共有10000条查询结果,搜索用时 221 毫秒
31.
A study comparing the macular function of both eyes of 130 urological surgeons was carried out to investigate whether the increased light exposure to the endoscoping eye caused any deterioration of macular function. The non-endoscoping eye was used as a control. A sophisticated computer test of colour contrast sensitivity was used. The computer assesses the degree of brightness at which the subject is just able to detect a coloured grating, and for each eye this is expressed as a threshold for the red/green axis and the blue/yellow (tritan) axis. The subjects also completed a questionnaire about their working patterns and their general and ophthalmic history and had a brief examination of the fundus. The results do not suggest that urologists are suffering any significant macular damage as a result of their work with endoscopes.  相似文献   
32.
33.
N C Dean  W C Amend  M A Matthay 《Chest》1987,91(4):619-620
A 21-year-old man developed the adult respiratory distress syndrome (ARDS) within five hours of receiving antilymphocyte globulin. No other identifiable cause of ARDS was present. The mechanism for development of acute lung injury is unknown, but may be related either to direct lung cytotoxicity or to complement-mediated leukocyte and platelet destruction with secondary lung injury from inflammatory mediators.  相似文献   
34.
Although major tissue trauma produces profound depression of cell-mediated immunity, it is not known whether surgical trauma (i.e., midline laparotomy) has any adverse effect on the antigen presentation function and membrane interleukin-1 (IL-1) activity of peritoneal macrophages. To study this, C3H/HEJ (endotoxin-tolerant) mice were anesthetized. An approximately 1-inch midline abdominal incision was made, followed by abdominal closure. On days 1, 3, 5, and 7, peritoneal macrophages were harvested by means of peritoneal lavage, and antigen presentation capability was tested by incubating various numbers of peritoneal macrophages with 2 X 10(4) D10.G4.1 cells per well in the presence of conalbumin (400 micrograms/ml). The T helper cell clone (D.10.G4.1) proliferates on recognition of conalbumin in the context of Iak and also proliferates in the presence of membrane-bound IL-1 plus concanavalin A. To measure membrane IL-1 expression in peritoneal macrophages, Concanavalin A (10 micrograms/ml) was substituted for conalbumin. Cultures were incubated for 72 hours, pulsed with tritiated thymidine, and harvested. Peritoneal macrophages from laparotomized mice induced significantly less T helper cell proliferation on days 1 and 3 in the antigen presentation assay (37% and 30%, respectively; p less than 0.05) and in the membrane IL-1 assay (14% and 10%, respectively; p less than 0.05) as compared with the control. This difference was not detectable on day 5. More effective antigen presentation capability (167% of control; p less than 0.05) was seen on day 7. Thus laparotomy by itself produces marked depression of both antigen presentation function and membrane IL-1 activity of peritoneal macrophages, which may enhance susceptibility to intra-abdominal sepsis.  相似文献   
35.
36.
Mechanisms of zinc (Zn) toxicity are incompletely understood and data regarding potential endocrine alterations in Zn toxicity are scarce. To examine mechanisms of Zn toxicity, day-old chicks were pair-fed diets containing 5280 ppm (Hz) or 73 ppm (CON) Zn. Impaired postnatal growth, independent of feed consumption, and multiple endocrinopathies were observed following short-term (1-2 weeks) exposure to the high Zn diet. Reduced levels of serum cholesterol, high-density lipoprotein cholesterol, and growth hormone were associated with HZ feeding. Depressed levels of circulating thyroid hormones and histological evidence that follicle area of thyroids from HZ birds was 63% less than CON indicated that impaired growth of HZ birds may be caused, in part, by reduced thyroidal function.  相似文献   
37.
We describe a two generation family with variable ulnar and radial ray reduction and midline craniofacial abnormalities. The features suggest a diagnosis of Weyers' ulnar ray/oligodactyly syndrome originally described in two isolated cases. Syndromes of ulnar ray reduction are briefly reviewed and the relationship between limb bud and midline development discussed.  相似文献   
38.
39.
An examination of the urinary excretions of 101 normal subjects indicated that the major genetic influence on calcium excretion is a codominant pair of alleles giving rise to three phenotypes, low, intermediate and high (hypercalciuric) excretors. This inference was based on variance, Hardy-Weinberg and segregation analyses. Similar independent gene pairs also appear to influence oxalate and citrate excretion, A 3-locus Hardy-einberg table using estimates of gene frequencies derived from the study of normals suggests that only 3 or 4 leading genes are involved in oxalate stone disease. Strong candidate genes identified from molecular and physiological studies cannot be proposed at present, but it is assumed that they influence the transport of these ions in either the intestine, kidney or both organs. The identification of the genes involved should be facilitated by the reduction of dietary influences on urinary excretions through the use of formula diets.  相似文献   
40.
Sulfasalazine (SASP) has often been reported to cause serious blood disorders, particularly agranulocytosis; however, little quantitative information is available to estimate the risk or to identify possible modifiers of the risk. We used comprehensive clinical information recorded on office computers by selected general practitioners in Britain to conduct a follow-up study of some 10,000 users of SASP and some 4000 users of mesalazine to estimate the risk of blood disorders associated with these drugs. Overall, the frequency of blood disorders attributable to SASP was 27/10,332 (2.6/1000 users). The risk for SASP users who were treated for arthritic disorders (6.1/1000 users) was some 10 times higher than that for users who were treated for inflammatory bowel disease (0.6/1000 users). There were no cases of blood disorders in users of mesalazine.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号